Solar System Log by Andrew Wilson, published 1987 by Jane's Publishing Co. Ltd.

On this Soviet attempt at a lunar soft-landing, the mission proceeded as planned until the major midcourse correction late on 9 June. Although the main retrorocket engine (the S5.5A) ignited on time, it failed to cut off and continued to fire until propellant supply was exhausted.

An investigation later indicated that the problem had been due to human error; a command had been mistakenly sent to the timer that ordered the main engine to shut down. Although the spacecraft was sent on a completely wrong trajectory, ground controllers put the spacecraft through a series of steps to practice an actual landing, all of which were satisfactorily accomplished.

Luna 6 passed by the Moon late on 11 June at a range of 161,000 kilometers and eventually entered heliocentric orbit. Contact was maintained to a distance of 600,000 kilometers from Earth.

Key Dates

8 Jun 1965: Launch

Status: Unsuccessful

Fast Facts

This was the Soviet Union's third attempt to make a survivable landing on the Moon.

Although it missed the Moon, mission controllers used the flight to practive for an actual landing.

The Soviet Union launched 10 of the 15 interplanety spacecraft sent into deep space in 1965.